1. Technical Field
The present invention relates to an image forming apparatus, such as a printer or a copying machine.
2. Related Art
In a conventional image forming apparatus using an electrophotographic method or an electrostatic recording method, it is general that an image carrier is electrically charged by using a discharge charging member, such as a corotron or a conductive roller to which a bias is applied.
In the discharge charging method, it is not avoidable that discharge products generated by the discharge are attached on an image carrier, such as a photoconductor. If a large amount of discharge products are attached on the image carrier, the electrical characteristic of a surface layer (for example, a photoconductor layer) of the image carrier corresponding to portions, in which the discharge products are attached, is changed under high humidity environment because the discharge products have hygroscopic properties. As a result, there is a possibility that a phenomenon, in which an image becomes white, will occur. In particular, in a condition in which an image forming apparatus is placed under the high humidity environment for a long time, the hygroscopic properties of the discharge products increase even more, and accordingly, the phenomenon in which an image becomes white occurs more frequently.
Here, in order to remove the discharge products, for example, a brush-shaped cleaning member having a high front end force may be used. In this case, however, a photoconductor layer on the image carrier is abraded by the brush and abraded remainder is reattached onto the image carrier, and as a result, an external additive of toner is attached with the reattached remainder as a core. Accordingly, a raindrops shaped filming phenomenon (hereinafter, referred to as a raindrops shaped filming according to the necessity) is apt to occur and the image carrier is apt to be easily scratched because the front end force of the brush is strong. In addition, in order to remove the discharge products by using a blade-shaped cleaning member, it is possible to remove the discharge products by optimizing a parameter of the blade, however, the contact pressure becomes large, which causes a problem in that the blade is bent or makes a noise due to the rubbing and further the image carrier is abraded or the blade itself is abraded (teeth of a blade edge is broken or locally abraded). As a result, the lifetime of the image forming apparatus is shortened.